Apparatus for drilling lateral bores deviating from vertical well bores



Feb. 16, 1954 J. A. zUBLlN 2,569,428 vAPPARATUS FOR LLING LATERAL BoREs DEVIATING FRo ERTICAL WELL BoREs Filed Jan. 1v, 1951 3 Sheets-Sheet l INVENTORA ATTORNEYS 3 Sheets-Sheet 2 Feb. 16, 1954 1 A ZUBUN APPARATUS FOR DRILLING LATERAL BORES DEVIATING FROM VERTICAL WELL BORES Filed Jan. 17, 1951 IN VENT OR (fahr/1.525%

BY 4,W @0m ATTORNEYS Feb. 16, 1954 Filed Jan. 17, 1951 J. A. ZUB N APPARATUSFOR DRILLING LATERAL BOREIS DEVIATING FROM VERTICAL WELL BORES 3 Sheets-$heet 5 INVENT OR Jai/Alva Enf/: m @mvg-M ATTORNEYS Patented Feb. 16, 19574l APPARATUS FOR DRILLING LATERAL BORES DEVIATING FROM VERTICAL WELL BORES John A. Zublin, Los Angeles, Calif.

Application January 17, 1951, Serial No. 206,363

(Cl. Z55-1.6)

3 Claims. 1

The present invention relates to apparatus for drilling lateral bores deviating from existing vertical well bores.

It is an object and purpose of the invention to provide a set of apparatus elements that can be employed by drilling crews versed in the art of rotary drilling through the employment of practices with which they are generally conversant.

More specically, it is the object of the invention to provide a specially related drilling unit and Whipstock in which the whipstock and drilling unit effectively cooperate to initiate and insure the drilling of a deviating bore.

In its more specific aspects, the invention contemplates the employment in combination of a relatively short rigid curved drill guide suspended from a flexible drill string section and a specially constructed whipstock arranged to hold the rigid curved drill guide against rotation during the initiation of the drilling of a deviating well bore, while at the same time causing a drill carried by the rigid curved drill guide to be pressed sidewardly against the existing well bore, all in combination with means for positively rotating a drill bit carried by the rigid drill guide through rotation of a drill string extending to the well surface. Further and more detailed objects and advantages of the invention will become apparent as the description proceeds, in which will be given a reference to the accompanying drawings, wherein:

Figure 1 is a view in side elevation disclosing the apparatus of the present invention in the posltion occupied thereby on the initiation of the drilling of a deviating bore from an existing vertical well bore.

Figure 2 is an enlarged detailed View partly in cross section showing the position of the whipstock and rigid drill guide immediately prior to contact thereof.

Figure 3 is a detailed view partly in cross section showing the manner of connecting the rigid curved drill guide into the drill string and illustrating the internal bit driving member.

Figure 4 is a detailed cross sectional view through the lower end of the rigid curved drill guide illustrating the manner in which the bit is supported. 1

Figure 5 is a, detailed view partially in cross section showing the internal construction of the Whipstock and illustrating the same at right angles to the position occupied thereby in Figures 1 and 2.

Figure 6 is a transverse cross sectional view on line 6--6 of Figure 2.

Figure 7 is a fragmentary detailed view of the tool employed in setting and orienting the whipstock.

Figure 8 is a view similar to Figure 1 but showing a modified form of the invention.

Figure 9 is a detailed view taken at right angles from Figure 8, and

Figure 10 is a cross sectional view taken on line IU-I 0 of Figure 9.

When it is desired to drill a lateral bore deviating from an existing vertical well bore with the apparatus of the present invention, the rst step resides in setting the whipstock which may, if desired, be oriented to insure the drilling of the deviating bore in the desired azimuth and at the proper vertical position in the existing well bore. For this reason the description herein will be initiated with a description of the specially constructed whipstock, its manner of orientation and setting in a well.

At one or more sections of coupling rod l I carried by the lower end of the body of the whipstock and at the lower end of the coupling rod I l there is threadedly received therein a iishtail bit l2. The body I0 of the whipstock has a cylindrical cavity I3 into which there projects a rib I4 integral with the whipstock body I0. An open keyway I5 extends from the upper end of the cylindrical cavity I3 through the top of the whipstock. The top of the whipstock is curved and the degree of curvature corresponds to the degree of curvature of the rigid curved drill guide presently to be described and which is received in and seats in the semi-circular saddle it which is disposed centrally along a transverse axis of the whipstock.

Referring to Figure 7, the tool for setting and orienting the whipstock embraces a generally rectangular shaped head Il carried by a vertical shank I8 which is adapted to be secured to a small pipeline I9 that extends to the surface of the well. The rectangular head Il of this tool passes freely through the open keyway l5 in the body I D of the whipstock and is accommodated by the cylindrically shaped cavity I3 in which the head Il of the tool may be given a partial rotation. As soon as the head Il of the tool is rotated out of alignment with the keyway i5, the whipstock will be suspended thereby and can be lowered into the well. The length of and number of the sections II between the body Illv of the whipstock and the shtail bit l2 will determine the distance above the bottom of the hole at which the deviating bore is to be drilled., When the tool comprised of the small pipeline I9, shank I8 and head il is rotated beyond, say a quarter turn, the head Vl strikes against the rib i4 integral with the body lil of the whipstock and further rotation of the tool effects rotation of the whipstock, thus the Whipstock can be oriented so as to position the curved saddle I3 in relation to the existing well bore to insure the drilling of a deviating bore fin the desired azimuth. When the Whips't'ock has been ,properly oriented, it-'can be lowered so that the teeth of the fishtail bit l2 dig in slightly into the formation of the bottom of the well and lock the whipstock against rotation toV an undesired position. A reverse rotation of the tool, including the head "il, will bring it again into alignment with the open keyway l5 andY permit its removal from the whips'tockiand withdrawal from the well, leaving the whipstock ready to receive the rigid curved drill guide.

Coming next to that portion of the apparatus which is carried at the lower end of the conventional rotary drill strng, the lower .end rof the lower section of the conventional rotary drill string i's'indicated a't'20 in Figure 1. lv"Fnreadedly attached to the lower end 2li of the lower section ofthe conventional rotary drill string is a Ilexible non-resilient drill string section '2l which preferably takes the 'form of 'the `-non-resilient flexible drill pipe more particularly -disclosed in my'prior U. S. 'Patent'2,5l`53v66 issued on July i8,

1950. It will be appreciated that, depending upon the length of the deviating bore desired Ato `be drilled, one or more non-resilient flexible pipe sections 42| may be employed in theapparatus.

To the lower end of the flexible non-resilient drill string section 2li lthere is vattac'heda tubular coupling member'2`2 (see Figuref). The coupling member 2'2 -has a relatively long extension 23 on which an annular bearing member .'24 is mounted. The `bearing member 24 is provided with a ball race 25 in which ball bearings 23 are adapted to ride. Roller bearings El' v.are also carried intermediate the annular bearing member 24 and the tubular extension 23 `of the coupling 22. The lower end of the tubular extension f2.3 of the coupling `22 threadedly receives a second exible non-resilient tubular member 23 which, apart 'from the fact that it is Vof somewhat 4less diameterV than the flexible 'non-resilient .tubular drill string section 2l, may b'e of the same -construction. Both 'the flexible non-resilient drill string section 2l and the .flexible non-resilient member 23 are made up of small 'independent units interconnected `by 'the dovetail slots in a manner described in more detail in U. S. Patent 2,515,366 hereinabove referred to. 'Each .o "f lthe members 2l and 28 is also provided with an vimpervious flexible liner such as indicated va'tZl in Figure 3 secured at its opposite ends to the ilexible metallic tubular member through `the medium of a combined threadedandYrvet'connection such kas indicated `at`3l) ineach of Figures `3 and 4. -Secured to the lower end of the flexible non-resilient tubular member 23 is a second tubular coupling member 3l whichvait its .lower end threadedly receives the shank vr32 of the 'bit 33 -carrying 'the conical cutters 34. A .shortiannular bearing member 35 Asurrounds lthe smaller portion of the tubular coupling'memberBl Vand is .provided with ball race '36 in which'the ball bearings 31 ride. Roller bearings 38 are also disposed intermediate the Short 'annular bearing member 35 and the smaller portion of the tubular (coupling 'member 3|. At either end of the flexible non-resilient tubular member '28 'there'is disposed a set of ball bearings 39. At the lower end of the flexible non-resilient member 28 the ,said ball bearings 39 rest and ride on the upper `smaller 'diameter tubular member 23 effects a 'p'ositiverotationo'f the bit 33.

Animportant feature of the present invention .resides in 'the rprovision of a short rigid curved drill guide lll that surrounds the flexible nonresilient tubular member 23 and is connected at its upper end by the threaded connection 4I to the short annular bearing member 2li and at its lower end through the threaded .connection 42 to the short annular bearing member (seefF-igures 3 and 4). Roller 'bearings 'A3 and 21B zare mounted intermediate the outer relatively short curved rigid drill guide 4B and the 'inner flexible tubular drill guide member 28. lt willbe appreciated that in operation the short rigid curved drill guide il@ and the short annular bearing members 2d and 35 at the upper and lower ends respectively of the curved drillgu'ide '4D do not rotate, Whereas the tubular coupling memberZl, the flexible non-resilient tubular member 128 and the tubular coupling 3l secured'to the 'lower end of the member 22 "do rotate in vunison when the rotary drill string, including the flexible nonresilient drill string section 2i is rotated.v The arrangement is such that substantiallyall frictional VContact between the rotating elements of apparatus and `the non-rotating rigid curved drill guide lll .and the associatedbearing mem' of the apparatus embracing the flexible non-resilient tubular drill string section Y21 the flexible tubular drill guide member '28, the curved rigid drill guide memberil andthe'bit 33 'are'lowered into the Well and rotated so thatthedirection of curvature of the rigid drill 'guide T50 extends along the same transverse axis-.as the curvature of the senil-circular seat IGin the whipstock, the rigid drill guide MJ will 'move into .the seat 'f6 "in the manner indicated in '.'Figure l. lvWhen'tlie elements of the apparatus 'are in the v.position show-n in Figure l, `rotation vvof the drill string at the surface of the well effects 'rotation "ofthe exible 'non-resilient drill string section '21, the inner flexible Anon-resilient drill guide mem'ber 28 and the bit 33, while the curved rigid drill guide 'All lis held'ag'ainst rotation due :toits Ebeing seated 'in the 'curved semi-circular'seat l5 of the whips'tock. The pressure imposed `on't'he 'area of contactfbetween thelourve'ddrillfguide fand the semi-circular seat l '6 Yfof the whip'stock due 'Lto the lweight vof the A'drill string causes rthe l:bit'33 to be forced against lthe side 'of the vertical '-well boreand rotation of the bit thus initiatesfdrilling of a deviating bore. The rigidrcurved guide v40 follows the bit under the pressure fimposed thereon and when the curved-guide 40 has=com pletely lentered a deviating bore, the flexible/nonresilient drill string section 2| then follows the semi-circular 1curved seat I6 of the Whipstock and progressesinto the deviating'wellbore as'the same is advanced through continued rotation of the drill bit.

It will be observed that the only non-rotating element entering the deviating bore is the short curved drill guide 40. Thus, no extended nonrotating elements are either in the curved deviating bore or in the vertical well bore about which the mud fluid can set during intervals of cessation in the circulation thereof. It will be additionally observed that the curved guide 40 may progress into a deviating bore many times the length thereof.

The length and degree of curvature of the rigid curved drill guide and the corresponding degree of curvature of the semi-circular seat IE of the whipstock will be determined by the diameter of the existing vertical well bore from which a deviating bore is to be drilled. Generally speaking, the rigid curved drill guide 40 will be four or five times as long as the diameter of the vertical well bore into which it is to be inserted and the degree of curvature of the rigid curved drill guide 40 will be such that it can pass freely into a vertical well bore having a diameter equal to at least one-fifth of the over-al1 length of the rigid curved drill guide 40.

Referring to Figures 8 to 10, there is disclosed in these figures a modified form of the invention in which the rigid curved drill guide 40 carries a bit 45 having a body of greater transverse dimension than the diameter of the rigid drill guide 40. In this modification the rigid drill guide 4!! extends through the collar 46 of the whipstock 4i and the collar 46, together with the body of the blt 45, act to support the whipstoclc 41 from the lower end of the drill string during the lowering of the drill string into the well. A shear pin 43 may suitably be passed throuffh the body of the whipstock 41 and received into a suitable opening in the body of the bit 45 as shown in Figure 8. When the elements are in the position shown in Figure 8, the rigid curved drill guide 40, the bit 45 and the whipstock 41 can be lowered into the well as a unit. The cutters of the bit 45 lie within the confines of the periphery of the collar 46 of the whipstock 41 and do not gouge into the sides of the well bore as the bit is lowered into the well. When the fishtail bit 49 strikes the bottom of the well bore and weight is thereafter applied by the drill string to the curved drill guide 40, the pin 48 will be sheared off and the bit will be urged into the side of the well bore, at which time rotation thereof is initiated in the manner described with respect to the other modifications of the invention. The rigid curved guide 40 seats in the cut-out channel 50 of the whipstock 4l which holds the same against rotation and yet continues to urge the bit laterally as the curved guide 4l) is lowered to effect the initiation and drilling of a deviating curved bore.

The modification of Figures 8-10 possesses certain advantages in operation in that the whipstock and bit can be lowered into the well at one and the same time, requiring no extra round trip for setting the whipstock. Additionally, the bit is held during the period of insertion into the Well in a position out of contact with the wall of the well bore. Further, when the rigid curved drill guide 40 and the bit are withdrawn at the conclusion of the drilling of the curved deviating bore, the whipstock is withdrawn and pulled to the surface of the well, along with the rigid curved drill guide and bit.

While I have disclosed the whpstock as supported from the bottom of the well and locked against rotation by a lishtail bit, it will be appreciated that it is within the broader purview of the invention to employ slits associated with the whipstook for locking the same against the walls of the vertical well bore in the desired position.

The foregoing specification has been given by way of exemplication of the invention and not in limitation thereof, the scope of the invention being that defined by the subjoined claims.

What I claim is:

l. A unit attachable to the lower end of a rotary drill string and insertable into a vertical Well bore for drilling lateral bores deviating from existing vertical well bores comprising in combination a first non-resilient flexible tubular drill string member, means for securing the upper end of said flexible drill string member to the lower end of a conventional rotary drill string, a second non-resilient flexible tubular member secured to the lower end of said first flexible tubular member and rotatable in unison therewith, a drill bit secured to the lower end of and rotat able in unison with said second flexible tubular member, a short rigid curved drill guide carried on and surrounding said second flexible nonresilient tubular member, said second flexible non-resilient tubular member being free to rotate within said rigid drill guide, means rotatably securing said bit to the lower end of said guide, a whipstock, means carried by the whipstock for seating and holding said rigid curved drill guide against rotation while said flexible non-resilient members and said bit are rotated to initiate drilling of a lateral bore deviating from a vertical bore on a curvature of the same radius as the radius of curvature of said short rigid curved drill guide, whereby said flexible non-resilient members and said rigid curved drill guide follow the bit into a curved deviating bore as drilled thereby.

2. A unit attachable to the lower end of a rotary drill string and insertable into a vertical well bore for drilling lateral bores deviating from existing vertical well bores comprising in combination a rst non-resilient exible tubular drill string member, means for securing the upper end of said flexible drill string member to the lower end of a conventional rotary drill string, a second non-resilient flexible tubular member secured to the lower end of said first flexible tubular member and rotatable in unison therewith, a drill bit secured to the lower end of and rotatable in unison with said second flexible tubular member, a short rigid curved drill guide freely suspendable in a vertical well bore carried on and surrounding said second flexible non-resilient tubular member, said second flexible nonresilient tubular member being free to rotate within said rigid drill guide, means rotatably securing said bit to the lower end of said guide, a whipstoek, means carried by the whipstock for seating and holding said rigid curved drill guide against rotation while said flexible non-resilient members are rotated to advance said bit and said rigid curved Vguide into a lateral bore deviating from a vertical bore on a curvature of the same radius as the radius of curvature of said short rigid curved drill guide and means carried by the whipstock for holding the same against rotation in the well bore when set for the drilling of a deviating bore in the desired azimuth.

3. A unit attachable to the lower end of a rofairy' driii siring and insertabie inte e vertical Weill bore for drilling lateral bores devia/ting from existing Vertical Weill bores comprising in eembilnaten a firstnon-ifesilent .flexible tubular ldrill string member, means fork securing the upper end "of said iexibl'e drill 'string member to 'the lower emi` of a conventional rotary driii string, a second non-resilient ii'exibie drill'v string tubuiar member of l'ess outside diameter iban vsaid first member secured. to the lower 'endl of .said first exible tubular member and rotatable in unsn therewith, a drill bit secured to the lower end of and rotatable in unison with said second flexibie. tubular memberl, a'.v curved tubular one-piece drill. guide carried on. and :surrounding saisi' second. flexible .non-resilient. tubular member and having diameter not substantially greater than. that: of .said first membei', .said second iiexibie .non-resilient tubular member being 'free 'to rotate Within said curved driii guide. means 1'otatab-ly securing said bit to' the llo'wer end of said guide; l:sai-dY bite being4 Ie'ective to 'drifli a bore of greater `diameter than the- .m'aximiim diameter of the. unit, 'etA Whipstock, means carried vby the Whipstock for seating and holding said curved drI-i guide-against rotation while said 'exible noni-esiiient1-members and said bit are rotated to drill -alateral bore deviating from a vertical bore on va curvature of the same radius as Vtine radius of cmvature 'ofV said curved drill guide.

JOHN A. ZUBLIN.

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